ASSOCIATION BETWEEN GLYCATED HEMOGLOBIN (HBA1C) AND FASTING BLOOD GLUCOSE LEVELS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS IN PESHAWAR: A CROSS-SECTIONAL STUDY

Abstract

Type 2 Diabetes Mellitus (T2DM) is a major metabolic disorder requiring effective assessment of glycemic control. Fasting blood glucose (FBS) reflects blood glucose levels at a specific point in time, whereas glycated hemoglobin (HbA1c) provides an indication of longer-term glycemic exposure. Understanding the relationship between FBS and HbA1c is particularly important in settings where HbA1c testing may be less accessible or more costly. This study aimed to determine the association between fasting blood glucose and HbA1c levels among patients with Type 2 Diabetes Mellitus attending Sugar General Hospital, Hayatabad, Peshawar. It also aimed to determine whether FBS significantly predicts HbA1c and to assess whether age and gender influence or moderate this relationship. A hospital-based, cross-sectional observational study was conducted among 385 adult patients with Type 2 Diabetes Mellitus aged 30 years and above at Sugar General Hospital, Hayatabad Phase V, Peshawar. Participants were identified prospectively during the study period through the routine hospital clinical workflow when their physicians advised both fasting blood glucose (FBS) and HbA1c testing. Eligible patients provided written informed consent, and their Medical Record (MR) numbers were collected. Demographic information and corresponding FBS and HbA1c results were retrieved from the hospital Laboratory Information System. The laboratory\ tests were performed as part of routine clinical care and were not specifically conducted for this research. Participants were selected using a non-probability convenience sampling technique. Data was analyzed using SPSS. Pearson correlation, simple linear regression, and hierarchical multiple regression were performed, with statistical significance set at p < 0.05. The mean age of participants was 51.19 ± 11.95 years, while the mean HbA1c and FBS levels were 8.90 ± 2.57% and 181.42 ± 87.29 mg/dL, respectively. A statistically significant, moderately strong positive correlation was observed between FBS and HbA1c (r = 0.570, p < 0.001). Simple linear regression demonstrated that FBS significantly predicted HbA1c (F (1,383) = 183.88, p < 0.001) and explained 32.4% of the variance in HbA1c (R² = 0.324). In hierarchical regression, age and gender did not significantly moderate the FBS–HbA1c relationship. The FBS × Age interaction was not significant (p = 0.638), and the FBS × Gender interaction did not reach statistical significance (p = 0.059). The study demonstrated a significant positive association between fasting blood glucose and HbA1c among patients with Type 2 Diabetes Mellitus in Peshawar. FBS was a significant predictor of HbA1c; however, the observed association does not support treating FBS as a substitute for HbA1c. Age and gender did not significantly alter the relationship between FBS and HbA1c in this sample. FBS and HbA1c therefore provide related but distinct information about glycemic status.